Changes in odour-active compounds of two varieties of Colombian guava (Psidium guajava']java L.) during ripening

Changes in the concentrations of odour-active compounds in two varieties of Colombian guava (Psidium guajava L.) fruits during ripening were followed by application of stable isotopic dilution analyses (SIDA). The data revealed that, in particular, the concentration of C-6-aldehydes, as well as the amount of the sulphur compounds 3-sulphanylhexyl acetate and 3-sulphanyl-1-hexanol, decreased with ripening, while the concentrations of aliphatic esters and furanones increased during this process. A calculation of odour activity values indicated that although the C-6-aldehydes decreased during ripening, these still made the greatest contribution to the overall aroma at all stages of ripening. Changes in odour-active compounds in white- and pink-fleshed guavas showed the same behaviour.